Mineral extracting apparatus having crank mounted rotary cutter



April 39%? G. DOMMANN MINERAL EXTRACTING APPARATUS HAVING CRANK MOUNTEDROTARY CUTTER Filed Aug. 7, 1964 INVENTOR Q J'MTER. fidfl/BIA NN A Tfo//uays United States Patent 3,313,576 MINERAL EXTRACTING APPARATUS HAVINGCRANK MOUNTED ROTARY CUTTER Giinter Dommann, Wethmar, near Lunen,Germany, as-

signor to Gewerkschaft Eisenhutte Westfalia, Wethmar, near Lunen,Westphalia, Germany, a corporation of Germany Filed Aug. 7, 1964, Ser.No. 388,083 Claims priority, application Germany, Aug. 16, 1963, G38,485 11 Claims. (Cl. 299-53) The present invention relates to amineral extracting apparatus, and more particularly to such an apparatusfor the winning or extraction of mineral from the upper portion of amine face deposit which remains after the lower portion of such mineraldeposit, such as coal, has been removed, as for instance, by long wallplaning mine operations.

When extracting mineral, such as coal, by planing and cuttingtechniques, as are often used in long wall mining, only the lower layersor at best the lower and middle layers of the mineral seam are loosenedfrom the deposit in the usual manner by a positive force, i.e. byplaning operations. The undercut, upper portion of the mine seamdeposit, as a rule, breaks apart and caves in later on by itself due tothe fact that such upper portion is robbed of its support. However, thisis not always the case, especially where the mineral deposits are verythick, such as where the mine face being extracted is of extraordinaryheight with regard to the usual dimensions of the mineway and the rangeof operation of the usual mining planer apparatus. Where such verticallythick of extraordinarily high seams of mineral, such as coal, areencountered, it is advisable and even necessary to win or extract theupper portions of the mine face also by positive force, in order toavoid the formation of too large an overhang of upper portion coal orother mineral which could interfere with the mine supports requiredbetween the mine floor and the mine roof to stabilize the condition ofthe mineway and which could also endanger the personnel working at themine face. The positive force required to extract the overhangingmineral or upper level mineral from a mine face of extraordinary heightmay be provided in terms of manual labor, with the use of coal pickhammers, etc., although the mechanical or automatic winning orextraction of mineral such as coal has been attempted in the pastbecause of the increase in efiiciency possible thereby.

For instance, it has been proposed already, in the case of winning orextracting coal to include an additional coal planer along the upperpart of the row of pit props or mining props which are located adjacentthe coal face in the mineway or mine shaft. Such coal planer is supposedto move along the roof of the mine seam exposed thereat, whereby toperform a paring or peeling action on such roof coal. In this way, notonly the upper portion of the coal deposit but also the coal whichremains in the middle strata will be loosened effectively. However, sucha device requires a support at the mine face which is considerablyheavier than usually provided, in

.view of the mine face which understandably must be kept open to permitthe planer to extract the roof coal and upper seam coal yet providesufficient safety for the personnel working at the mine face.

It is an object of the present invention to overcome disadvantages anddrawbacks of previous mining arrangements for the extraction of mineralfrom the upper portion of mine seams, especially those of extraordinaryheight or vertical thickness.

It is another object of the present invention to provide a mineralextracting apparatus adapted to be displaced back and forth along a mineface for extracting overhanging mineral from the upper portion of a mineface, particularly one of extraordinary height, after the lower portionthereof has been extracted.

It is a further object of the present invention to provide a mineralextracting apparatus of the foregoing type which may be used inconjunction with elevated, elongated guide means adapted to bepositioned longitudinally along the mine face, such that the mineralextracting apparatus of the invention will be guided at a pre-determinedelevation above the mine floor corresponding to the level of theoverhanging mineral in the upper portion of the mine face to beextracted.

It is a still further object of the present invention to provide amineral extracting apparatus of the foregoing type which accomplishesthe winning or extracting of mineral from the upper portion of the mineface by alternate thrusts of eccentrically mounted rotatable cuttingtools, preferably in fiat, conical disc form.

It is a still further object of the present invention to provide anarrangement of the foregoing type utilizing a mineral extractingapparatus, in which the guide means is a mining conveyor of theconventional type, such as a double chain scraper conveyor.

Other and further objects of the present invention will become apparentfrom a study of the within specification and accompanying drawings inwhich:

FIG. 1 is a schematic side view of a mineral extracting apparatus inaccordance with the invention mounted on a guide means in the form of amining conveyor shown in section, with a coal planer of the conventionaltype being arranged at the side of the conveyor adjacent the mine faceto illustrate the normal level of operation thereof in comparison withthe level of operation of the mineral extracting apparatus of theinvention,

FIG. 2 is a schematic top view of the mineral extracting apparatus ofthe invention showing details of construction and the operativeconnection of the single shaft embodiment with a driving motor, and

FIG. 3 is a schematic top view of a mineral extracting apparatus of thedual shaft embodiment illustrating the manner of operatively connectingsuch shafts with the driving motor therefor.

It has been found in accordance with the present invention that amineral extracting apparatus, especially useful for extrcatingoverhanging mineral from the upper portion of a mine face ofextraordinary height after the lower portion thereof has been extracted,may be provided. Such mineral extracting apparatus comprises a movablelbase adapted to be displaced back and forth along a mine face,rotatable shaft means mounted on said base and extending outwardlybeyond said base on the side thereof adjacent the mine face, a pair ofcorresponding crank portions located on the outwardly extending shaftmeans in axially displaced relation with respect to one another and inopposing rotatable relation for rotation out of phase with one another,and a corresponding pair of disc cutters positioned on said shaft meansat said crank portions, respectively, and adjacent such mine face forengaging extractively the mine face in alternate thrusts during rotationof said shaft means for the removal of mineral from such mine face.

Preferably, the disc cutters have about the same radius and arerotatable with respect to the shaft means, and the crank portions areout of phase about The crank portions, preferably also have a differenteccentricity from one another. In accordance with a specific embodimentof the invention, the disc cutters are substantially in the shape ofcones and have a cone axis which is substantially shorter than theradius of the cone base, such cone base being remote from the movablebase and adjacent the mine face.

Specifically, in accordance with the one particular embodiment of theinvention, the mineral extracting apparatus comprises a movable baseadapted to be displaced longitudinally back and forth along a mine face,a rotatable shaft mounted on said base, one end of the shaft extendingoutwardly beyond the base on the side of the base adjacent the mine faceand having a pair of opposing crank portions located in tandem thereon,and a pair of disc cutters positioned on the shaft at the crankportions, respectively, and adjacent such mine face for engagingextractively the mine face in alternate thrusts during rotation of theshaft for the removal of mineral from such mine face. More specifically,the pair of opposing crank portions are located about 180 apart axiallyin tandem on the shaft and the disc cutters have about the same radiusand are rotatable with respect to the shaft to effect the desiredextraction of mineral, such as coal, from the mine face in alternatetangential thrusts during rotation of the shaft. The crank portions asaforesaid preferably possess a different eccentricity from one anotherwith respect to the axis of the shaft.

In accordance with another particular embodiment of the presentinvention, the mineral extracting apparatus comprises a movable baseadapted to be displaced longitudinally back and forth along the mineface, a pair of substantially parallel spaced apart rotatable shaftsmounted on such base, one end of each shaft extending outwardly in thesame direction beyond the base on the side of the base adjacent the mineface, the end of one shaft extending outwardly axially beyond the end ofthe other shaft and both shafts having a crank portion at the outwardlyextending end thereof, said shafts being mounted for rotation such thatthe crank portions thereof are out of phase, and a pair of disc cutterspositioned 011 the shafts at the crank portions, respectively, andadjacent the mine face for engaging extractively the mine face inalternate thrusts during rotation of the shafts for the removal ofmineral from such mine face. More specifically, in the same way, thecrank portions are preferably out of phase about 180 and the disccutters have about the same radius and are rotatable with respect to thecorresponding shaft on which the particular disc cutteris positioned,whereby the eflfect the extraction of mineral in alternate tangentialthrusts during rotation of the shaft to which the particular disccutters is secured. In this case, as well, it is preferred to providethe crank portions with a different eccentricity from one another withrespect to the axis of the corresponding shaft.

Referring to the drawing, an embodiment is shown in FIGS. l and 2 inwhich a pair of disc cutters is provided on the same shaft whereas inFIG. 3 an embodiment is shown in which the disc cutters are provided onseparate shafts.

Thus, in FIG. 1, a mining arrangement is shown including a double chainscraper conveyor of the conventional type including the vertical sideWalls 11 and 12 and the horizontal central plate 13, such conveyor beingpositioned adjacent the mine face 16 along the extent thereof whereby toconvey away from the site of mining operations extractedmineral, such ascoal, conducted onto the upper side of central plate 13. Endless doublechains having their forward flights on the upper side of plate 13 andtheir return flights on the lower side of plate 13 are provided and suchchains are interconnected transversely by scraper bars spaced apartalong the chains to accomplish the conveying of mineral along the topside of central plate 13. Constructions of this type are well known.

Such conveyor is usually employed in conjunction with a mining planer 15of the usual type and the conveyor is disposed longitudinally along themine face to permit the planer 15 to be guided therealong in extractiveengagement with such mine face. As shown in FIG. 1, the conveyor 10 isprovided with a guide rail or pipe 14 on the vertical side wall 12adjacent the mine face 16 and the planer 15 is mounted for movementtherealong at groove 15a on the side of planer 15 remote from the mineface. The planer 15 extracts mineral up to a height'corresponding topoint 17 in mine face 16 and extracted mineral is plowed by the planer15 upwardly and rearwardly onto conveyor 10 along the upper side ofplate 13. The plowing is accomplished by suitably shaping the side face20 of planer 15 depending upon the direction of movement of such planer.The planer is conducted along the mine face by means of an endless chain18 connected at either side to planer 15 and having its return portion19 passing through the hollow pipe 14 attached to the conveyor 10, withthe ends of the drive chain being mounted on appropriate drive wheels atthe ends of the mineway in which the mining operation is carried out.Such drive wheel mountings for the chain are well known.

In order to stabilize the planer 15 in its movements back and forthalong the mine face, a keel or underlying transverse arm 21 is providedat the rearward side of the planer so that the same passes along themine floor 22 under the bottom of conveyor 10. The weight of conveyor10, especially considering the added weight of the extracted mineralbeing conveyed therealong, is sufficient to keep the planer upright andby suitable advancing means (not shown) attached, for example, tovertical side wall 11, the conveyor 10 and in turn the planer 15 may beurged constantly toward the mine face 16. Such advancing means may takethe form of a piston cylinder arrangement connected to a bracing pitprop in reinforcing engagement with the mine floor 22 and mine roof 36,whereby to constantly urge through the piston cylinder arrangement theconveyor, and in turn the planer toward the mine face 16.

As shown in FIG. 1, the vertical side wall 12 of conveyor 10 is providedwith a track 23 whereas the vertical side wall 11 is provided with aretaining flange 24 forming a groove 25 operatively parallel with thetrack 23. In this way the forward foot 26 and rearward foot 27 may besuitably mounted on track 23 and in groove 25, respectively, fordisplacement therealong so as to permit the carriage 28 of the mineralextracting apparatus of the invention to move back and forth adjacentthe mine face for the purposes desired. The feet 26 and 27 may beprovided in a constructional form to reduce sliding friction along track23 and groove 25, such as providing these feet as rollers, wheels, lowfriction slide runners, etc. The motor housing 29 is situated on thecarriage 28 and is provided with a shaft 30 rotatably mounted thereon.Such shaft contains integrally the crank portions 31 and 32, each ofwhich carries a disc cutter 33 and 34, respectively, preferably in theform of flat cones, i.e. in which the cone axis is substantially shorterthan the radius of the cone base. The cone base is preferably positionedremote from the housing 29 and adjacent the mine face 16. The disccutters are shown as having about the same radius and are preferablyrotatable with respect to the shaft 30 at the crank portions 31 and 32,respectively, to permit a tangential thrust to be exerted against theoverhanging roof mineral 35 at the upper portion of the mine face 16.The crank portions 31 and 32 are preferably out of phase about and byproviding these crank portions with a different eccentricity from oneanother, the appropriate disc cutters will attack the overhangingmineral 35 alternately and within a difierent peripheral range from oneanother. By the alternate thrusts of the disc cutters during rotation ofshaft 30, the removal of mineral from the overhanging portion 35 of themine face will be carried out most efiiciently.

As may be seen more clearly in FIG. 2, the shaft 30 is journaled at 37and 38 in housing 29 such that the beveled gears 39 and 40 transmit therotational force of shaft 41 to shaft 30, and in turn to the crankportions 31 and 32 and thence to the disc cutters 33 and 34. Drive shaft41 is connected via a suitable coupling 42 with motor 43 which may be ofany conventional type, such as electric motor or a compressed air motor,etc.

In the embodiment shown in FIG. 3, in place of the single shaft 36containing the eccentric crank portions 31 and 32 with appropriate disccutters thereon, a pair of separate, spaced apart substantially parallelshafts 45 and 48 are provided in housing 44, shaft 45 containingintegrally the crank portion 46 with the appropriate disc cutter 47thereon and the shaft 48 containing integrally the crank portion 49 withthe appropriate disc cutter 50 thereon. Shaft 45 is journaled at 51 and52 on housing 44 whereas shaft 48 is journaled at 58 and 59 on suchhousing in an offset manner to permit the operative connections betweendrive shaft 55 and the appropriate shafts 45 and 48 via the bevel gears53, 54, and 60, 61, respectively. in turn, the drive shaft 55 isjournaled at 62 and 63 on housing 44 and is operatively coupled via thecoupling 56 with the drive motor 57 which is analogous to motor 43 ofFIG. 2.

In the case of the dual shaft embodiment of FIG. 3, each crank portionis offset with respect to the other, and preferably such crank portionsare offset about 180 by the beveled gearing employed to achieve thealternate thrusts of the disc cutters 47 and 50 tangentially against theoverhanging mineral, such as coal, for the efficient extraction thereof.It is preferable, in this case, as well, to provide the disc cutterswith about the same radius and to provide the crank portions withdifferent eccentricities from one another with respect to thecorresponding shaft axis so that the range of each disc cutter will bedifferent and accordingly, the operation of one will complement theoperation of the other. In the same Way as in the case of the embodimentof FIGS. 1 and 2, one disc cutter is positioned closer to the mine facethan the other so that the horizontal thickness of mineral which may beworked by the mineral extracting apparatus may be increased.

By providing the disc cutters in each of the embodients as rotatable onthe crank portions of the particular shaft or shafts, i.e., freelyrotatable or rotatable independently of the rotation of such shaft orshafts, the disc cutters may thrust tangentially against the overhangingmineral and dig into the same yet give way by rotating on the particularcrank portion so as not to set up excessive forces in the apparatusduring contact with the overhanging mineral. Of course, by providing thecrank portions offset with respect to one another, and preferably 180apart, and by providing different degrees of eccentricity of such crankportions, preferably, as well as the positioning of one disc cuttercloser to the mine face than the other, the desired alternativeextractive engagement of the disc cutters will be enhanced within therange of operation permitted.

It will be realized that the embodiment shown in FIG. 3 is to be mountedon a carriage similar to carriage 28 as shown in FIG. 1 and all similarelements of each embodiment may actually be the same in construction andform, except with regard to the use of one shaft or two shafts and theappropriate bevel gearing and journaling required in each case.

With regard to the advantages of the present invention, it will beappreciated that the mine face 16, shown in FIG. 1, is of extraordinaryheight or unusual vertical seam thickness, and therefore the usualplaner can only accomplish the removal of the lower portion of themineral up to a height generally designated by the point 17. While someof the upper portion mineral will fall under its own weight, an overhang35 will still remain which must be removed if the mining extractionoperations are to be at all efiicient and safe. Since the mineralextracting apparatus of the invention is positioned for longitudinalmovement along the top of the conveyor 10 or other suitable guide means,the range of the disc cutters will be at the upper level of the mineface Well above the mine floor and the uppermost point 17 representingthe range of operation of the planer 15. As the normal mining operationsprogress and an overhang 35 is formed, then the planer 15 may bestopped, and the mineral extracting apparatus of the invention startedwhereby to remove the overhanging mineral, or if desired, depending uponthe circumstances, the operation of the planer and the mineralextraction apparatus of the invention may be carried out simultaneouslyinasmuch as separate vertical levels of operation are carried out bythese devices. It will be noted that flange 24 extends upwardly beyondthe upper end of conveyor 10 at side wall 11 in order to providesuitable reinforcement for the carriage 28 in the event excessive forcesare met at the mine face in the overhanging portion 35, for instance,which would otherwise derail carriage 28 or tilt the mineral extractingapparatus out of its normal operating position. It will be noted fromFIG. 1 that without the mineral extracting apparatus of the presentinvention, the overhanging mineral 35 could not be readily extracted andsuch mineral would either be lost or manual means for its extractionwould become necessary. Naturally, the height of the planer 15 cannot beextended indefinitely due to the operational limitations thereof, theweight thereof, the type of mineral being extracted, the unevenness ofthe mine floor and of the mine seam being worked, etc.

Naturally, as the shaft or shafts will be rotated, the disc cutters willthrust alternately aginst the overhanging coal from therebelowsufficiently to loosen the mineral whereby the same will fall under itsown weight. The intermittent thrusts of the disc cutters during eachrotation of the shaft or shafts provides an efiicient extracting of theoverhanging mineral without undue stress on the working parts, andpreferably in the embodiment utilizing two separate, spaced apartshafts, each with a separate disc cutter, the shafts are rotated at thesame speed and the disc cutters are of the same diameter, yet with thecrank portion of one shaft being of a different eccentricity from theother, whereby to acheive the even intermittent thrusts of theoverhanging coal without undue wear on the operating parts. Preferably,in the case of the embodiment using two separate shafts, such shafts arepositioned at the same height, although such shafts may be arranged atdifferent heights if desired. The latter possibility might be found mostuseful where the disc cutter closest to the overhanging coal does notreach as high as the other disc cutter so that the normal upward andoutward profile of the overhanging coal may be accommodated moreefiiciently in the extraction operations. The disc cutters when mountedon two separate shafts'at different heights will always attack the mineface at different heights correspondingly whereas in the usual casewhere both disc cutters are on the same shaft, such disc cutters willattack the mine face or overhanging mineral at substantially the sameheight.

While the eccentricity of the two crank portions may be the same, it isparticularly advantageous to provide the crank portion closest to themine face with the smaller eccentricity because of the advantage thatthe disc cutter which possesses a relatively small range of operation,i.e. when periodically swinging up and down or rotating, is thrustagainst the mine face with greater force than otherwise. Preferably, thedisc cutters are situated on the corresponding crank portions so thatsuch disc cutters may carry out a rotary motion with respect to theparticular shaft or shafts at least as long as the edge of the disccutter is in contact with the overhanging mineral. Thus, the disc cutterwill roll off or roll with the mine face surface bringing about apartial rotation of the disc cutter counter to the rotation of the crankportion and corresponding shaft.

It will be appreciated by the artisan that the mineral extractingapparatus of the invention may be adapted to varying conditionsdepending upon the vertical height of the mine seam and the upperportion thereof which is to be extracted. Thus, by suitable expedients,the range of elevation of the device in question may be varied, as forexample, by varying in turn the height of the guide means upon which themineral extracting apparatus may travel along the mine face. Moreover,the carriage 28 of the instant apparatus may be provided with adjustablefeet to adjust the height of the carriage from the mine floor or fromthe guide means, such as the conveyor, upon which the carriage may bemounted.

Advantageously, the carriage of the mineral extracting apparatus of theinvention should, if possible, be located on the conveyor such that oneor even both of the rotating disc cutters will be located more or lessimmediately above the conveyor side wall adjacent the mine face. In thisway, practically the entire upper portion of the mine face which isextracted by the loosening force of the disc cutters will be loadedautomatically into the conveyor. Unlike the mineral extracted from thelower portion of the mine face in the usual way by a planing apparatus,the extracted mineral does not have to be plowed or otherwise conductedonto the conveyor for removal.

It will be obvious to the artisan that while the mineral extractingapparatus of the invention may travel back and forth along the mine facewith the same frequency and speed as the normal planer for the mineralin the lower portion of the mine face, even so it might prove best toarrange the equipment in such a Way that the planer will pass back andforth along the mine face several times before the instant upper levelmineral extracting apparatus will have to travel back and forth alongthe mine face. In fact, it may only be necessary to travel in onedirection to extract the overhanging mineral whereupon the instant upperlevel apparatus may be stopped and only conducted in the oppositedirection after the usual planer extraction operations have been carriedout to a further extent whereby to expose a new portion of overhangingmineral. Experience has shown that less energy by far is required toextract mineral from the upper portion of the mine face than from thelower and/r middle portions thereof, and this is probably due to thefact that the upper portion is no longer supported between the minefloor and mine roof once the lower portion of the mineral deposit hasbeen removed. Naturally, in the overhanging upper portion mineral, suchmineral by its own weight will aid in the loosening occasioned by theinstant upper level apparatus.

Generally, the mineral extracting apparatus of the present invention maybe used where the range of vertical height of the mine seam which may beextracted by the usual planer is approximately only about A of theheight of the vertical seam. While the exact numerical value is notimportant, what is important is the fact that the height of the range ofextraction operations of the usual planer is only a fraction of theentire height of the deposit of mineral to be worked. In such cases, themineral in the upper portion of the seam will always overhang to agreater or lesser extent. The thrust effect of the rotating disc cuttersin accordance with the invention alternately brought against theoverhanging mineral in quick succession in consequence of the speed ofrotation of the shaft or shafts provides an excellent loosening effectwith a minimum of effort and wear and tear on the working parts, andthis is true whether both disc cutters are mounted on the same shaft oron separate, spaced apart shafts. Nevertheless, the advantage of theembodiment in which the disc cutters are on separate shafts as opposedto the embodiment where such disc cutters are on the same shaft, is thatone disc cutter together with its shaft may be removed if the situationis such that the remaining disc cutter is capable by itself of removingthe overhanging mineral in the upper portion of the mine seam.

While the disc cutters have been shown as substantially flat, conical OIdish-like elements, it will be realized by the artisan that such cuttersmay have different shapes, as for example the shape of a fiat doublecone, i.e. with the opposing apexes situated remote from one another.Inasmuch as the rotating cutting edges of the disc cutters areparticularly heavily taxed during the extraction operations of theoverhanging mineral, they may be equipped advantageously withreplaceable hard-metal tools or cutting blades in order to avoidpremature wear and tear.

It will be realized by the artisan that the foregoing specification anddrawings have been set forth by way of illustration and not limitation,and that various modifications and changes may be made without departingfrom the spirit and scope of the present invention, which is to belimited only by the scope of the appended claims.

What is claimed is:

1. Mineral extracting apparatus which comprises a movable base adaptedto be displaced back and forth along a mine face, rotatable shaft meansmounted on said base and extending outwardly beyond said base on theside thereof adjacent the mine face, a pair of corresponding crankportions located on and integrally connected with the outwardlyextending shaft means in axially displaced relation with respect to oneanother and in opposing rotatable relation for rotation out of phasewith one another, and a corresponding pair of disc cutters positioned onsaid shaft means at said crank portions respectively and adjacent suchmine face for engaging extractively the mine face in alternate thrustsduring rotation of said shaft means for the removal of mineral from suchmine face.

2. Apparatus according to claim 1 wherein said disc cutters have aboutthe same radius and are rotatable with respect to said shaft meansindependently of the rotation of such shaft means, and said crankportions are out of phase about 3. Apparatus according to claim 2wherein said crank portions have a different eccentricity from oneanother.

4. Apparatus according to claim 2 wherein said disc cutters aresubstantially in the shape of cones and have a cone axis which issubstantially shorter than the radius of the cone base, such cone basebeing remote from said movable base and adjacent the mine face.

5. Mineral extracting apparatus which comprises a movable base adaptedto be displaced longitudinally back and forth along a mine face, arotatable shaft mounted on said base, one end of said shaft extendingoutwardly beyond said base on the side of said base adjacent the mineface and having a pair of opposing crank portions located axially intandem thereon and integrally connected therewith, and a pair of disccutters positioned on said shaft at said crank portions respectively andadjacent such mine face for engaging extractively the mine face inalternate thrusts during rotation of said shaft for the removal ofmineral from such mine face.

6. Mineral extracting apparatus which comprises a movable base adaptedto be displaced longitudinally back and forth along a mine face, arotatable shaft mounted on said base, one end of said shaft extendingoutwardly beyond said base on the side of said base adjacent the mineface and having a pair of opposing crank portions located about 180apart axially in tandem thereon, and a pair of disc cutters of about thesame radius positioned on said shaft at said crank portions respectivelyand adjacent such mine face and rotatable with respect to said shaftindependently of the rotation of such shaft for engaging extractivelythe mine face in alternate tangential thrusts during rotation of saidshaft for the removal of mineral from such mine face.

7. Apparatus according to claim 6 wherein said crank portions have adifferent eccentricity from one another with respect to the axis of saidshaft.

8. Mineral extracting apparatus which comprises a movable base adaptedto be displaced longitudinally back and forth along a mine face, a pairof substantially parallel spaced apart rotatable shafts mounted on saidbase,

one end of each shaft extending outwardly in the same direction beyondsaid base on the side of said base adjacent the mine face, the end ofone shaft extending outwardly axially beyond the end of the other shaftand both shafts having a crank portion at the outwardly extending endthereof and integrally connected therewith, said shafts being mountedfor rotation such that the crank portions thereof are out of phase, anda pair of disc cutters positioned on said shafts at said crank portionsrespectively and adjacent such mine face for engaging extractively themine face in alternate thrusts during rotation of said shafts for theremoval of mineral from such mine face.

9. Mineral extracting apparatus which comprises a movable base adaptedto be displaced longitudinally back and forth along a mine face, a pairof substantially parallel spaced apart rotatable shafts mounted on saidbase, one end of each shaft extending outwardly in the same directionbeyond said base on the side of said base adjacent the mine face, theend of one shaft extending outwardly axially beyond the end of the othershaft and both shafts having a crank portion at the outwardly extendingend thereof, said shafts being mounted for rotation such that the crankportions thereof are out of phase about 180, and a pair of disc cuttersof about the same radius positioned on said shafts at said crankportions respectively and adjacent such mine face and rotatable withrespect to the corresponding shaft on which the particular disc cutteris positioned independently of the rotation of such corresponding shaftfor engaging extractively the mine face in alternate tangential thrustsduring rotation of said shafts for the removal of mineral from said mineface.

10. Apparatus according to claim 9 wherein said crank portions have adifferent eccentricity from one another with respect to the axis of thecorresponding shaft.

11. Mineral extracting arrangement for extracting overhanging mineralfrom the upper portion of a mine face of extraordinary height after thelower portion thereof has been extracted, which comprises elevatedelongated guide means adapted to be positioned longitudinally along amine face, a carriage mounted on said guide means for 5 movement backand forth thereon adjacent a mine face at a predetermined elevationabove the mine floor corresponding to the level of the overhangingmineral in the upper portion of the mine face, a motor means situated onsaid carriage for movement therewith, horizontal rotatable shaft meansoperatively connected to said motor means and mounted on said carriageand extending outwardly beyond said carriage on the side thereofadjacent the mine face, a pair of corresponding crank portions locatedon the outwardly extending shaft means in axially displaced relationwith respect to one another and in opposing rotatable relation forrotation out of phase about 180 with one another, and a correspondingpair of disc cutters positioned on said shaft means at said crankportions respectively and adjacent the mine face at said elevation androtatable with respect to said shaft means independently of the rotationof such shaft means for engaging extractively the overhanging mineral inthe upper portion of the mine face in alternate thrusts during rotationof said shaft means for removal of such mineral from the mine face.

References Cited by the Examiner UNITED STATES PATENTS 2,691,514 10/1954Lobbe 299 34 2,694,563 11/1954 Graham 29986 X 2,791,411 5/1957 Herrmann299-44 3,004,753 10/1961 Sik 299-86 X as FOREIGN PATENTS 879,923 10/1961Great Britain.

ERNEST R. PURSER, Primary Examiner.

1. MINERAL EXTRACTING APPARATUS WHICH COMPRISES A MOVABLE BASE ADAPTEDTO BE DISPLACED BACK AND FOURTH ALONG A MINE FACE, ROTATABLE SHAFT MEANSMOUNTED ON SAID BASE AND EXTENDING OUTWARDLY BEYOND SAID BASE ON THESIDE THEREOF ADJACENT THE MINE FACE, A PAIR OF CORRESPONDING CRANKPORTIONS LOCATED ON AND INTERGRALLY CONNECTED WITH THE OUTWARDLYEXTENDING SHAFT MEANS IN AXIALLY DISPLACED RELATION WITH RESPECT TO ONEANOTHER AND IN OPPOSING ROTATABLE RELATION FOR ROTATION OUT OF PHASEWITH ONE ANOTHER, AND A CORRESPONDING PAIR OF DISC CUTTER POSITIONED ONSAID SHAFT MEANS AT SAID CRANK PORTIONS RESPECTIVELY AND ADJACENT SUCHMINE FACE FOR ENGAGING EXTRACTIVELY THE MINE FACE IN ALTERNATE THRUSTSDURING ROTATION OF SAID SHAFT MEANS FOR THE REMOVAL OF MINERAL FROM SUCHMINE FACE.